<style>
    #box-container {
        background: gray;
        display: flex;
        height: 500px;
        align-items: center;
    }
    #box-1 {
        background-color: dodgerblue;
        width: 200px;
        font-size: 24px;
    }

    #box-2 {
        background-color: orangered;
        width: 200px;
        font-size: 18px;
    }
</style>

<div id="box-container">
    <div id="box-1"><p>Hello</p></div>
    <div id="box-2"><p>Goodbye</p></div>
</div>